The second movement of Mozart's Sonata in C, K.309 (K.V.284b) is an Andante un poco adagio. It is expressive and displays lovely elaboration of the thematic material. Mozart composed this sonata in Mannheim in 1777. At the time, he was teaching a young woman named Rosa Cannabich. In one of several letters to his father which mention this sonata, Mozart wrote in 1777 that "I am with Cannabich every day... He has a daughter who plays the clavier quite nicely; and in order to make a real friend of him I am now working at a sonata for her, which is almost finished save for the Rondo... The Andante will give us most trouble, for it is full of expression and must be played accurately and with the exact shades of forte and piano, precisely as they are marked...." The reply from Mozart's father Leopold: "Nannerl (Mozart's sister) plays your whole sonata excellently and with great expression. If you leave Mannheim, as I now presume you will, I shall have it copied and enclose a small sheet in every letter, so that you may have it again. Your sonata is a strange composition. It has something in it of the rather artificial Mannheim style, but so very little that your own good style is not spoilt thereby." The sonata was first published by Heina in 1782 as Opus 4.